Various techniques have been developed to deal with electrocution and electric shock hazards at boat docks and marinas. Hazards arise because power installations, either at shore or on boat locations, can leak electrical current into surrounding water. Causes of leakages include live power supply cords falling into the water, poorly insulated or corroded equipment, short circuit, mis-wiring, hot or active ground wires, stray voltage, or other electrical faults. It has been reported that two hundred cases of fatalities at marinas have occurred due to stray current leaking into surrounding water. Where leaked electrical current affects the muscles of a swimmer to cause or contribute to a drowning, the electric shock may not be revealed upon autopsy causing the threat to be hidden or under-reported. In addition to the threat to humans, pets, and aquatic marine life, the stray current can cause (metal) boats and marina objects to be corroded by electrolysis, and, in some circumstances, can spark fires.
A paper entitled “Worker Deaths by Electrocution” dated Can 1998 and published by the U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Health and Safety indicates that moisture increases the possibility of low-voltage electrocution. Swimming, standing in water, wearing wet clothing, high humidity, and perspiration all contribute to the risk. According to the NIOSH paper, under dry conditions, the resistance offered by the human body can be as high as 100,000 Ohms. Wet or broken skin can drop the body's resistance to 1,000 Ohms. An example illustrates how moisture affects low-voltage electrocutions: under dry conditions, Current=Volts/Ohms=120/100,000=1 mA, a barely perceptible level of current. Under wet conditions, Current=Volts/Ohms=120/1,000=120 mA, sufficient current to cause ventricular fibrillation. The NIOSH paper concludes that wet conditions are common during low-voltage electrocutions.
Attempts have been made to address some of the root causes of unwanted stray current being displaced into water, such as replacing equipment (household components such as power bars, extension cords, automotive battery chargers, etc.) with marine approved power cables and receptacles, or installing equipment such as circuit breakers, polarity indicators (to warn of reversed polarity), residual current devices such as ground fault circuit interrupters, electrical leakage circuit interrupters, isolation transformers, marine approved tinned stranded copper wires (not solid strand “house wire”), etc. However, equipment such as fuses or circuit breakers may not trip as the resistance of surrounding water may not allow the passage of sufficient current to blow a fuse or trip a circuit breaker.
Occurrences of stray current leakages into water persist and hazards are often difficult to detect and diagnose because few or no readily observable symptoms are present. There are even some reports of first responders attempting rescue but themselves succumbing to electrocution or electric shock, unaware that the first victim's swimming difficulties were caused or exacerbated by undetected stray current. In some situations, protective equipment such as insulating rubber boots or shoes (or other personal protective equipment or “PPE”), wooden planking that can be kept dry covering wet floors, etc. can be used, but this equipment is not convenient or suitable for use in many scenarios such as swimming in waters surrounding a marina.
Improvements in electrical testers and measuring instruments for detection of electrical properties in a liquid are desirable.
The foregoing examples of the related art and limitations related thereto are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings.